What Is the BMI Threshold for Repairing a Ventral Hernia?

Luise I Pernar, MD1, Claire H Pernar, MPH2, Bryan V Dieffenbach, MD1, David C Brooks1, Douglas S Smink1, Ali Tavakkoli, MD1. 1Brigham and Women’s Hospital, 2Harvard School of Public Health

Introduction: Overweight and obese patients are often asked to lose weight prior to attempts at ventral hernia repair (VHR). Improved short as well as long term outcomes are cited as reasons behind this strategy; however, limited long term success of non-surgical weight loss means that this strategy mostly influences short term outcomes. Therefore, it is critical to know at what body mass index (BMI) threshold postoperative complications increase in order to properly counsel patients.

Methods and Procedures: All patients who underwent VHR at our institution between 2002 and 2015 captured in the NSQIP database were included. The primary outcome was defined as having any (≥1) of 18 captured postoperative complications. Patients were divided into five groups based on BMI: group 1 (<25 kg/m2); 2 (25-29.99 kg/m2); 3 (30 to 34.99 kg/m2); 4 (35-39.99 kg/m2); and 5 (≥40 kg/m2 ). Multivariable logistic regression was performed to evaluate the association between BMI categories and postoperative complication, adjusting for age, gender, race, current smoking status, history of severe COPD, presence of ascites within 30 days of surgery, diabetes mellitus, and steroid or other immunosuppressant use.

Results: 67 of 922 patients (7.3%) had at least one postoperative complication following VHR; patients in BMI group 5 were most likely to experience a complication: 5.6% of patients in group 1 had a complication, 5.7% in group 2, 6.2% in group 3, 6.5% in group 4, and 16.5% in group 5. The adjusted risk of complications among patients with BMI ≥40 kg/m2 was 3.2 times greater compared to patients with BMI <25 kg/m2 (OR 3.2; 95% CI=1.4-7.4). No significant differences in risk of postoperative complications were observed for groups 2, 3, or 4 compared to group 1. BMI category was significantly associated with undergoing recurrent versus initial VHR, with 28% of patients in BMI group 5 having a recurrent repair compared to 14% in patients in BMI group 1 (p=0.03 )

Conclusions: After VHR, complications are most likely to occur in patients with BMI >40kg/m2.  This subset of patients also had a significantly higher risk of undergoing surgery for a recurrent hernia, suggesting that this group of patients are likely to experience adverse outcomes after VHR and should be counseled to undergo bariatric surgery prior to attempts at VHR. VHR at lower BMIs appears appropriate and delaying therapy to achieve pre-operative weight loss will likely offer no advantage. 

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